Stiffening of the gluteal muscle increased the intramuscular stress: An in-silico implication of deep tissue injury.

Objectives: Deep tissue injury is a common form of pressure ulcers in muscle tissues under bony prominences caused by sustained pressure or shear, which has a great impact on patients with restricted mobility such as spinal cord injury. Frequent spasms in spinal cord injury patients featured by muscle stiffening may be one of the factors leading to deep tissue injury. The purpose of this study was to investigate the relationship between the gluteal muscle shear modulus and intramuscular compressive/shear stress/strain. Methods: A semi-3D finite element model of the human buttock was established using COMSOL software and the acquired biomechanical data were analyzed through Pearson correlation and Spearman correlation. Results: Results showed that the compressive stress, strain energy density, and average von Mises stress increased with the increase of the gluteal muscle shear modulus. Conclusion: These results may indicate muscle stiffening caused by muscle spasms could lead to higher deep tissue injury development risk as well as shed light on effective treatments for relieving muscular sclerosis mechanically.